Called "Hypervelocity" stars, giant balls of gas are recently discovered to be leaving our galaxy.
These stars travel at speeds of over 1500000 kilometers per hour (roughly 932057 mph), and have enough kinetic energy to overpower the galaxy's gravitational force...sending them off into space.
The weird part? They're thought to originate from the galactic core, where gravity is the strongest.
The current accepted theory is, in simple terms, that the immensely strong gravitational field gives the star the necessary energy to escape the galaxy.
Think of spacecraft using the moon as a booster, per say.
Our black hole, which has the mass of four million of our suns, easily creates enough energy to throw just about anything in the galaxy far, far away.
How common are these anomalies? There are only 20 known stars to have performed this. To put that into perspective, that's a 20/3000000000 chance of being a "hypervelocity" star.